How to Fix RetroPie HDMI Not Outputting Sound
Here's a quick fix that, in most cases, will fix your no-sound issue from RetroPie. Commands entered are listed below.
1) In RetroPie's main menu, push start, then select Quit EmulationStation.
2) Once in the terminal, type: cd /boot
3) Then type: sudo nano config.txt
4) Once in the editor, find the line (about halfway down) that reads: #hdmi_drive=2
5) Remove the "#" in front of "hdmi_drive=2"
6) While holding the control key, push the "x" key on your keyboard.
7) When asked if you'd like to save, push the "y" key on your keyboard. Then press enter.
8) You should be back in the terminal. Now, you just need to type in "emulationstation" with no spaces, and press enter. This will reboot EmulationStation and take you back to its main menu. If this did not fix your audio issue, you may have to reboot the Raspberry Pi completely for the change to take affect.
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